Hey, this is a known issue. MCP servers can show as connected and you might see tools in the logs, but the agent still doesn’t pick them up in the session.
A few workarounds that have helped other users with the same problem:
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Toggle the MCP server off and on in Cursor Settings > Tools & MCP. This forces a re-init. Sometimes toggling any MCP server triggers a refresh for all of them.
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Start a fresh chat after toggling. Existing sessions might not pick up newly available tools.
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Mention the MCP server by name in your first message. Instead of a generic prompt, try something like: “Using the Docs by LangChain MCP, search for LangGraph error handling docs.” This can nudge the agent to discover the tool.
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There might be a timing delay between the server showing as connected in the UI and the agent actually having access to the tools. Waiting a moment after it connects, then starting a new chat, can help.
A couple questions:
- What status does the LangChain Docs server show in Settings > Tools & MCP, green, yellow, or red?
- Is this configured globally
~/.cursor/mcp.jsonor at the project level.cursor/mcp.json?
The team is aware of this pattern and tracking it. Your report helps with prioritization.
Related threads:
- MCP servers configured but agent cannot use their tools
- MCP tools only available after toggling off/on
Let me know how it goes.